1. Technical Field of the Invention
The present invention relates to a fitness machine and particularly to a fitness machine which primarily offers a stepping exercise.
2. Prior Art
As an example of the conventional fitness machine which primarily offers a stepping exercise, there is a type as shown in FIG. 9 in which the user obtains a stepping exercise by stepping on the right and left foot platforms S alternately. Another example is a type as shown in FIG. 10, in which a hand support H is secured to the base thereof such that the user rests his or her hands thereon to support his or her weight, or there are provided a pair of such hand supports adapted to be respectively swung back and forth such that the user swings the hand supports back and forth in coordination with his or her stepping actions, thus simultaneously giving a workout effect also to the upper part of his or her body.
As shown in FIG. 11A and FIG. 11B, on the other hand, there is a conventionally proposed type, in which hydraulic cylinders C by which right and left foot platforms are supported to offer a load resistance thereto. Forwardly of said right and left platforms S, there is arranged a swinging plate R, which is adapted to rotate about a pivot Q. When one of said foot platforms S is stepped on downward, the other one of the foot platforms S is adapted to be raised in coordination therewith. Further, the adjusting knob T is adjusted to cause said pivot Q to be shifted in the arrow-marked directions such that the downward stroke Y of said stepping is adjusted.
Further, as shown in FIG. 12A, the fitness machine of this type has a problem that even the same weight (of the stepping force) can magnify a force F in pressing the cylinders C by way of the foot platforms S if the angle .alpha. which the hydraulic cylinders C defines is small with the result that the cylinders C give the feel of less load resistance against the stepping force P.
In this way, the mere provision of said foot platforms S as shown in FIG. 9 only causes a simple motion such as elevating and lowering of the user's body in its entirety as a result of alternately stepping on his or her right and left heels, thus giving workout effects to lower part of the body in a limited range alone. Further, the effect brought about by the machine with the hand support H is limited to the motion of the upper part of the body while the lower part thereof is left unattended to.
On the other hand, the type shown in FIG. 11 which performs adjustment of the downward stepping stroke Y of the foot platform S not only has a complicated structure but also creates a problem that if the angle .alpha. of the cylinder C is extended as shown in FIG. 12B, the force pressing the cylinder is reduced even if the same weight P (or the stepping force) is applied thereto, thus giving the feel of heavier resistance to the stepping. The load resistance caused in stepping onto the foot platforms S is offered by the cylinders C. If an attempt is made to make the feel of such load resistance less by manipulating the adjusting knob T, the stepping stroke Y is made less while if the feel of the load resistance is attempted to be less, a larger stepping stroke Y is needed. In this way, the adjustment of the load adjustment is difficult problem.